The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Conventional machining uses high volume flow of a liquid lubricant over the cutting edges of the tool. Some tools having multiple cutting diameters have internal passages that provide this liquid lubricant to each cutting edge. Since the liquid lubricant is essentially an incompressible fluid, flow from each passage to each cutting edge remains substantially based on the pressure of the liquid supplied to the tool.
In contrast, minimum quantity lubrication (“MQL”) machining uses lubrication supplied to the cutting edges of a tool through a lean air-oil mist, rather than through the high volume liquid-based emulsion in conventional machining. Tools designed for liquid lubricant flow through internal passages suffer from unbalanced lubricant flow when used with the air-oil mist of MQL machining. The ratio of air to oil in the air-oil mist is typically very high and the lubricant mist acts as a compressible fluid (unlike the incompressible liquid lubricant of conventional machining). As a result, a disproportionate volume of the compressible lubricant mist tends to exit the tool via the passages at the larger diameter cutting edges, despite the majority of the cutting taking place at the smaller diameter cutting edges. This can result in wasted lubricant and excess wear on the tool.
The teachings of the present disclosure provide a cutting tool and method of manufacturing a cutting tool having a more balanced lubrication flow for MQL machining that overcomes the problems of typical cutting tools when used for MQL machining.